From DE 10 2006 025 348 A1 a power-split transmission having a variator designed as hydrostatic device is known. The power-split transmission is equipped with a power splitting planetary gear set, wherein a shaft of the planetary gear set is operatively connected to a first shaft of the variator, and in this manner an adjustable pump can be driven. An additional shaft of the planetary gear set is connected via a gear wheel to a second shaft of the variator, which, in turn, is operatively connected to a hydraulic motor of the variator. The third shaft of the planetary gear set is connected to a transmission input of the power-split transmission which is connected to a drive device.
In addition, the second shaft of the variator is designed with a plurality of fixed gears which mesh with a plurality of idler gears arranged on a countershaft, wherein the idler gears can be connected rigidly to the countershaft via shift elements to implement different driving modes and/or transmission ratios for forward driving and at least one driving mode for reverse driving.
Disadvantageously, the alternation between the driving modes cannot be carried out in a synchronous manner, so that to avoid an interruption in torque flow, in any case during a change in driving mode, power shifting with simultaneous correction of transmission ratio must be carried out in the region of the hydrostatic device. During such shifts, under certain circumstances disturbing reactive torques in the drive train of a work machine occur, which negatively impact a sequence of operation of a work machine equipped with the above-described power-split transmission and are perceived by an operator as a jerk in the working machine.